I've no time for folk who go off in a huff when there's work to be done

David McLetchie, Scottish Tory leader

Mr McLetchie told the gathering in Perth: "I have expressed and will express no public preference between them.

"But what I do pledge is my wholehearted unequivocal 100% support for the victor, and I expect everyone else in this party to have the sense and maturity to do the same.

"I've no time for folk who go off in a huff when there's work to be done."

It is thought Mr Clarke will try to persuade delegates that he can stop the party's drift to the right and provide a serious challenge to New Labour.

But Mr Duncan Smith is likely to argue that he is untainted by past failures and can reinvigorate the party faithful.

Ken Clarke: Toasts Scottish delegates

The conference is hugely important to both candidates, as it is effectively the last major platform they will have to pitch for Scottish votes before the 11 September deadline.

Arriving at the conference on Saturday, Iain Duncan Smith was met by Scottish deputy chairman Bill Walker who had earlier warned that the Tories should remember that prominent eurosceptics donated �40m to party funds at the last election.

A party spokesman denied this amounted to an open public endorsement of Mr Duncan Smith by the man who will be the neutral chairman of the Scottish hustings.

He said: "It is not a comment about the leadership elections but about Bill's position on Europe."

Mr Duncan Smith brushed aside comments by shadow Cabinet Office minister Andrew Lansley who claimed racism was endemic within the Conservative Party.

Ethnic minorities

Mr Lansley, who is backing leadership rival Ken Clarke, claimed the party had to do more to tackle the problem, and increase the number of Tory MPs from ethnic minorities.

Mr Lansley's comments follow the recent dropping from Mr Duncan Smith's campaign team and subsequent expulsion from the party of Edgar Griffin, a British National Party sympathiser.

Mr Duncan Smith denied the party was racist.

He said: "I believe that we are a party that is tolerant and inclusive.

"We always have been and always must be.

I believe that we are a party that is tolerant and inclusive.

Iain Duncan Smith

"Therefore, under my leadership, that's the party I want to reach out to all sorts of people regardless of colour, creed or religion - all to be part of what essentially is a party for one nation."

The party's London headquarters announced on Friday that more than half of its members had already voted in the leadership contest.

Acting Tory chairman David Prior said that 181,300 votes - from the 318,000 membership - had been cast at the half way stage in the ballot.

With voting due to close in 12 days time, both candidates now know how many votes are still up for grabs as they take the campaign trail to Scotland.

Notable contributions

Mr Clarke and Mr Duncan Smith will be given 45-minute slots at the conference to make their case and answer questions.

Although their struggle will rightly take centre stage there will be other notable contributions.

Iain Duncan Smith arrives for the hustings

The conference opened with Euro MP Struan Stevenson MEP and European group leader, Edward Macmillan-Scott.

Mr McMillan-Scott warned the party not repeat previous errors on Europe.

He said the Tories should unite and provide a coherent message on Europe as they did at the 1999 European Parliament elections.

One of the loudest cheers of the day will be reserved for Peter Duncan, the Ayrshire man who put the Scottish Tories back in Westminster by taking Galloway and Upper Nithsdale in the June election.

Mr Duncan will tell delegates why he thinks the party managed to take this seat yet failed miserably elsewhere.

He will also touch on the continuing difficulties posed by foot-and-mouth disease in his constituency and share his thoughts on the West Lothian question.

It is thought that Mr Duncan will use the platform to explain his decision to abstain from voting on all Westminster legislation, which affects England and Wales only.